I bought a Mario Kart power wheel for $25 from a woman on Craigslist. She said that it would only go in reverse. When I get home, plug it in and let it charge overnight, and give it a try in the morning, it doesn't move at all. I hear a buzz sound from the relay by the battery. Sometimes the buzz last for a second then I hear the motor turn but the wheel doesn't move. (single motor drive)

Could a bad f/r switch cause the relay to buzz? Or is the relay bad? Or any suggestions.